class CreateDelayedJobsKetcher < ActiveRecord::Migration
  def self.up
    unless table_exists?(:delayed_jobs)
      create_table :delayed_jobs, force: true do |table|
        table.integer :priority, default: 0, null: false # Allows some jobs to jump to the front of the queue
        table.integer :attempts, default: 0, null: false # Provides for retries, but still fail eventually.
        table.text :handler,                 null: false # YAML-encoded string of the object that will do work
        table.text :last_error                           # reason for last failure (See Note below)
        table.datetime :run_at                           # When to run. Could be Time.zone.now for immediately, or sometime in the future.
        table.datetime :locked_at                        # Set when a client is working on this object
        table.datetime :failed_at                        # Set when all retries have failed (actually, by default, the record is deleted instead)
        table.string :locked_by                          # Who is working on this object (if locked)
        table.string :queue                              # The name of the queue this job is in
        table.timestamps null: true
      end

      add_index :delayed_jobs, [:priority, :run_at], name: "delayed_jobs_priority"
    end
  end

  def self.down
    drop_table :delayed_jobs if table_exists? :delayed_jobs
  end
end
